Search This Blog

Sunday, November 22, 2015

U.S. Announces 2% Autism Rate. Again. And It’s Dependent on a Change in the Way a Survey is Worded. Again.

Last week a study was released showing an autism “rate” in the U.S. of about 2% (an estimated prevalence of 2.24% to be exact). Luckily one of the best science journalists out there focuses a lot of her attention on autism and covered this story.I’m writing of course about Emily Willingham and her article Increase In Autism Diagnoses Not An Increase In Autism.

While other articles are discussing the large “increase in autism”. Or, as in this Reuters article, U.S. autism numbers soar in which we read what must be a confusing message to many:"The results reflect a near doubling in autism rates over the past three years, but the U.S. Centers for Disease Control, which released the data last week, says the shift is largely due to a change in the way the survey was worded."

Thankfully much of the media, and even Autism Speaks, are pointing out how this 2% figure doesn’t represent a “real” change in autism prevalence, but is largely dependent on the study methods. Others can be counted on to shout “epidemic” and ignore some of the key reasons why this doesn’t reflect a real increase.

Number 1 reason – the autism prevalence is basically the same for kids who were 3-10 and kids who were 11-17:

A real increase would show up as a higher prevalence for younger kids.

One thing we see is a decrease in disparity for autism prevalence by race/ethnicity. African Americans have a slightly lower autism prevalence (it’s unclear whether this is statistically significant or not), and Hispanics have a decidedly lower autism prevalence (1.49% vs. 2.55% for Caucasians).Which means we still have far to go to identify and bring services to all autistics.And it also means that the autism prevalence estimates will continue to rise as we do identify more in under diagnosed populations.

But let’s focus on the important part of that–we still have a large under-diagnosed/under-served population and it is largely among Hispanics. We really need to be focusing more attention on remedying that situation.

Here is the abstract for the current study:ObjectivesThe developmental disabilities questions in the 2014 National Health Interview Survey (NHIS) were changed from previous years, including question reordering and a new approach to asking about autism spectrum disorder (ASD).This report examines survey-based estimates of the lifetime prevalence of ASD, intellectual disability (ID), and any other developmental delay (other DD) following the inclusion of a standalone ASD question, the inclusion of specific diagnoses in the ASD question, and the ASD question preceding the other DD question, and compares them with estimates from previous years.

MethodsIn NHIS, one child is randomly selected from each family to be the subject of detailed questions on health conditions, functional limitations, and health care utilization. Parents are asked if a doctor or health professional had ever told them that their child had each of a series of developmental disabilities.Prevalence estimates of ASD, ID, and other DD for children aged 3–17 years were calculated using data collected in 2011–2014.

ResultsThe estimated prevalence of ASD based on 2014 data was 2.24%, a significant increase from the estimated annualized prevalence of 1.25% based on 2011–2013 data. In contrast, the prevalence of other DD declined significantly from 4.84% based on 2011–2013 data to 3.57% based on 2014 data. The prevalence of ID did not significantly change from 2011–2013 (1.27%) to 2014 (1.10%). The prevalence of having any of the three conditions was constant across survey years.ConclusionsThe revised question ordering and new approach to asking about developmental disabilities in the 2014 NHIS likely affected the prevalence estimates of these conditions.In previous years, it is likely that some parents of children diagnosed with ASD reported this developmental disability as other DD instead of, or in addition to, ASD. Following these changes, the 2014 ASD estimate was more similar to ASD prevalence estimates from other sources.

No comments:

Post a Comment

Editor

What You'll Find

Fresh, carefully assembled content, including current research, of interest and value to the families of children and adolescents with special needs, and providers caring for them.

Topics include learning and developmental disabilities, autism, NLD, ADHD, executive function deficits, anxiety, issues involving general and special education law and civil rights, poverty and trauma as they affect students and their families and occasionally, metro-Boston calendar listings.

This material is selected to inform, provoke thought and stimulate dialog. We intend no endorsement or representation of scientific or medical validity.

SND - Special Needs Digest is not affiliated in any way with any business, group or organization.